The first step has been to teardown my old Psion 5 to harvest its excellent keyboard. This was made very easy thanks to the guide by Peddy on iFixIt.

With the keyboard now in hand, it was time to connect it to RasmusB's fantastic USB Keyboard Adapter for Psion 5/5MX. Before starting the project I had looked to order the adapter, but Rasmus said it was currently out of stock. After about five or six weeks I got a Tindie alert saying he had another batch available, and within seconds I'd placed my order. It arrived in the UK from Sweden after about 5 days, which I thought was exceptionally fast.

The adapter is tiny with a port for the keyboard and a Micro USB port. It comes with the software preloaded on an ATMEGA32u4 CPU and is pretty much plug and play. I wanted to update the firmware and change the key-mapping, but having little experience with Arduino, I struggled. Luckily, Rasmus is a remarkably friendly guy and was on hand to help me out by giving me step by step instructions via email. Thanks Rasmus!

I tested the keyboard and the adapter by plugging them into both my MacBook and my PC. It worked perfectly on both! Next it was time to try and make it Bluetooth compatible....